Anomalous spring observations

Published

March 6, 2025


We identified observations of plant phenophases in Nature’s Notebook (NN) that were earlier than normal in 2025. We compared 2025 observations with observations collected in 2009-2024 for plants within 100 km and within 1000 m elevation of the plant observed in 2025. We limited analyses to phenophases in 4 phenophase classes: initial vegetative growth (class 1), leaves or needles (3), flowers or cones (6), and open flowers or cones (7), and only evaluated whether an observation was early if there were at least 20 observations for that species and phenophase over 8 or more years between 2009 and 2024.

We classified a 2025 observation as early if it was earlier than 95% of first-of-year observations in 2009-2024, and as an outlier if it was a Tukey outlier (2025 observation earlier than Q1 - 1.5 * IQR). We also noted if the observation was as early or earlier than the earliest date ever recorded in NN for that species, phenophase, and region (earliest).

In the tables below, we list all of the 2025 observations that were considered early or an outlier by phenophase class. Histograms displaying distribution of observations in prior years that were used to assess 2025 potential anomalies are at the bottom of the document.

Table 1: Anomalous observations of initial vegetative growth. ID = individual plant identification number. No. Prior Obs. (Yrs) lists the number of 2009-2024 observations (with the associated number of years) that were used to determine whether a 2025 observation was anomalous or not.
Species Functional type ID State Lat Lon Elev (m) Date Early Earliest Outlier No. Prior Obs. (Yrs)
Pacific poison oak Deciduous broadleaf 270778 CA 37.93 -122.74 74 2025-01-18 Yes No No 57 (13)
common snowberry Deciduous broadleaf 253531 OR 44.94 -123.02 50 2025-01-21 Yes Yes Yes 69 (13)
golden currant Deciduous broadleaf 150497 NM 35.10 -106.68 1508 2025-01-20 Yes No No 33 (10)
northern spicebush Deciduous broadleaf 335285 PA 40.33 -74.94 27 2025-01-17 Yes Yes Yes 28 (9)
northern spicebush Deciduous broadleaf 348399 PA 40.33 -74.94 27 2025-02-19 Yes Yes Yes 28 (9)
northern spicebush Deciduous broadleaf 348400 PA 40.33 -74.94 27 2025-02-19 Yes Yes Yes 28 (9)
pecan Deciduous broadleaf 246701 OK 34.77 -96.66 315 2025-02-07 Yes No Yes 38 (8)
red alder Deciduous broadleaf 78535 CA 37.92 -122.69 0 2025-01-16 Yes No No 37 (13)
sugar maple Deciduous broadleaf 205360 NY 43.01 -78.78 168 2025-02-21 Yes No No 133 (9)
sweetgum Deciduous broadleaf 283106 NC 35.17 -81.06 197 2025-02-04 Yes Yes Yes 27 (11)
sweetgum Deciduous broadleaf 336128 NC 35.28 -81.09 226 2025-02-07 Yes Yes Yes 24 (10)
California live oak Evergreen broadleaf 87340 CA 37.36 -122.13 97 2025-01-21 Yes No No 279 (14)
California live oak Evergreen broadleaf 28811 CA 37.93 -122.74 75 2025-01-26 Yes No No 325 (14)
California live oak Evergreen broadleaf 87339 CA 37.36 -122.13 97 2025-01-30 Yes No No 279 (14)
Table 2: Anomalous observations of leaves or needles. ID = individual plant identification number. No. Prior Obs. (Yrs) lists the number of 2009-2024 observations (with the associated number of years) that were used to determine whether a 2025 observation was anomalous or not.
Species Functional type ID State Lat Lon Elev (m) Date Early Earliest Outlier No. Prior Obs. (Yrs)
American beech Deciduous broadleaf 335283 PA 40.33 -74.94 27 2025-01-24 Yes Yes Yes 26 (9)
northern red oak Deciduous broadleaf 204864 NY 43.01 -78.78 168 2025-02-13 Yes Yes Yes 39 (10)
northern red oak Deciduous broadleaf 204866 NY 43.01 -78.78 168 2025-02-13 Yes Yes Yes 39 (10)
northern red oak Deciduous broadleaf 204863 NY 43.01 -78.78 168 2025-02-17 Yes No No 39 (10)
northern red oak Deciduous broadleaf 204858 NY 43.01 -78.78 168 2025-02-18 Yes No No 39 (10)
red maple Deciduous broadleaf 204873 NY 43.01 -78.78 168 2025-02-18 Yes No No 63 (8)
red maple Deciduous broadleaf 204875 NY 43.01 -78.78 168 2025-02-18 Yes No No 63 (8)
red maple Deciduous broadleaf 199342 NY 43.01 -78.78 168 2025-02-21 Yes No No 63 (8)
red maple Deciduous broadleaf 204872 NY 43.01 -78.78 168 2025-02-21 Yes No No 63 (8)
sugar maple Deciduous broadleaf 297758 MA 42.37 -71.15 12 2025-02-03 Yes Yes Yes 233 (16)
sugar maple Deciduous broadleaf 205362 NY 43.01 -78.78 168 2025-02-14 Yes Yes Yes 144 (8)
sugar maple Deciduous broadleaf 205366 NY 43.01 -78.78 168 2025-02-19 Yes No Yes 144 (8)
sweetgum Deciduous broadleaf 336128 NC 35.28 -81.09 226 2025-02-07 Yes Yes Yes 23 (8)
Eastern Mojave buckwheat Drought deciduous broadleaf 31968 CA 34.68 -120.04 357 2025-01-10 Yes Yes Yes 28 (10)
blue paloverde Drought deciduous broadleaf 50745 AZ 32.25 -110.91 746 2025-01-12 Yes No No 78 (11)
blue paloverde Drought deciduous broadleaf 257146 AZ 32.40 -110.98 767 2025-01-21 Yes No No 78 (11)
catclaw acacia Drought deciduous broadleaf 237801 AZ 32.40 -111.00 801 2025-01-10 Yes Yes Yes 24 (9)
desert willow Drought deciduous broadleaf 50750 AZ 32.25 -110.91 746 2025-01-12 Yes No Yes 88 (12)
desert zinnia Drought deciduous broadleaf 278921 AZ 32.40 -111.00 801 2025-01-10 Yes No No 46 (8)
honey mesquite Drought deciduous broadleaf 11431 CA 34.13 -116.04 602 2025-02-03 Yes No Yes 24 (12)
ocotillo Drought deciduous broadleaf 139414 AZ 32.25 -110.91 746 2025-01-26 Yes No No 142 (15)
velvet mesquite Drought deciduous broadleaf 257140 AZ 32.40 -110.98 767 2025-01-21 Yes No No 104 (13)
black grama Graminoid 343755 NM 32.59 -106.84 1330 2025-01-15 Yes No No 199 (8)
black grama Graminoid 343756 NM 32.59 -106.84 1330 2025-01-15 Yes No No 199 (8)
black grama Graminoid 343768 NM 32.59 -106.84 1330 2025-01-15 Yes No No 199 (8)
Table 3: Anomalous observations of flowers or cones. ID = individual plant identification number. No. Prior Obs. (Yrs) lists the number of 2009-2024 observations (with the associated number of years) that were used to determine whether a 2025 observation was anomalous or not.
Species Functional type ID State Lat Lon Elev (m) Date Early Earliest Outlier No. Prior Obs. (Yrs)
buck-horn cholla Cactus 117070 AZ 33.60 -111.81 533 2025-02-06 Yes No No 79 (9)
Siberian elm Deciduous broadleaf 63893 NM 35.10 -106.68 1508 2025-01-20 Yes No No 54 (11)
arroyo willow Deciduous broadleaf 29433 CA 37.92 -122.69 0 2025-01-16 Yes Yes Yes 43 (13)
arroyo willow Deciduous broadleaf 275211 CA 38.05 -122.87 25 2025-01-17 Yes Yes Yes 43 (13)
black elderberry Deciduous broadleaf 4194 CA 34.46 -119.71 229 2025-01-22 Yes No No 289 (13)
eastern redbud Deciduous broadleaf 347346 MD 39.03 -77.02 109 2025-01-30 Yes Yes Yes 66 (8)
flowering dogwood Deciduous broadleaf 210868 NC 35.83 -82.55 693 2025-02-13 Yes No No 153 (12)
red maple Deciduous broadleaf 210872 NC 35.83 -82.55 693 2025-01-28 Yes No Yes 227 (14)
red maple Deciduous broadleaf 335280 PA 40.33 -74.94 27 2025-02-01 Yes Yes Yes 24 (9)
red maple Deciduous broadleaf 326716 PA 39.81 -76.35 154 2025-02-03 Yes Yes Yes 50 (8)
star magnolia Deciduous broadleaf 79974 CA 38.38 -122.51 109 2025-02-06 Yes No No 25 (8)
sugar maple Deciduous broadleaf 210871 NC 35.83 -82.55 693 2025-02-10 Yes Yes Yes 33 (9)
sweetgum Deciduous broadleaf 153521 LA 30.05 -89.88 0 2025-01-07 Yes No No 28 (8)
bald cypress Deciduous conifer 127552 LA 30.05 -89.88 0 2025-01-15 Yes No No 37 (8)
brittlebush Drought deciduous broadleaf 199265 AZ 32.34 -110.98 764 2025-01-14 Yes Yes Yes 65 (9)
ocotillo Drought deciduous broadleaf 321434 AZ 33.60 -111.81 533 2025-01-31 Yes No No 39 (10)
California live oak Evergreen broadleaf 28811 CA 37.93 -122.74 75 2025-01-19 Yes No Yes 190 (13)
California live oak Evergreen broadleaf 87340 CA 37.36 -122.13 97 2025-01-21 Yes No No 147 (13)
California live oak Evergreen broadleaf 87339 CA 37.36 -122.13 97 2025-01-30 Yes No No 147 (13)
coyotebrush Evergreen broadleaf 18492 CA 37.98 -122.13 63 2025-01-06 Yes Yes Yes 364 (14)
creosote bush Evergreen broadleaf 246469 AZ 32.37 -110.97 800 2025-01-05 Yes Yes Yes 209 (13)
creosote bush Evergreen broadleaf 102258 AZ 32.24 -110.91 755 2025-01-10 Yes Yes Yes 207 (13)
creosote bush Evergreen broadleaf 50751 AZ 32.25 -110.91 746 2025-01-12 Yes No No 207 (13)
creosote bush Evergreen broadleaf 199258 AZ 32.34 -110.98 764 2025-01-14 Yes No No 209 (13)
creosote bush Evergreen broadleaf 257149 AZ 32.40 -110.98 767 2025-01-19 Yes No No 209 (13)
jojoba Evergreen broadleaf 50747 AZ 32.25 -110.91 746 2025-01-09 Yes Yes Yes 90 (13)
jojoba Evergreen broadleaf 50746 AZ 32.25 -110.91 746 2025-01-12 Yes No No 90 (13)
olive Evergreen broadleaf 347073 CA 37.57 -122.03 12 2025-01-16 Yes Yes Yes 29 (10)
redbay Evergreen broadleaf 151042 MS 30.50 -89.67 18 2025-01-30 Yes No No 68 (8)
redbay Evergreen broadleaf 151043 MS 30.50 -89.67 18 2025-01-30 Yes No No 68 (8)
redbay Evergreen broadleaf 250659 MS 30.40 -88.65 0 2025-02-05 Yes No No 86 (8)
wax myrtle Evergreen broadleaf 283389 LA 30.32 -89.94 3 2025-01-12 Yes No No 56 (8)
wax myrtle Evergreen broadleaf 283390 LA 30.32 -89.94 3 2025-01-12 Yes No No 56 (8)
Douglas-fir Evergreen conifer 28798 CA 37.93 -122.74 74 2025-01-18 Yes No No 31 (13)
eastern redcedar Evergreen conifer 84087 NY 41.75 -74.12 89 2025-01-29 Yes Yes Yes 38 (11)
blue oak Semi-evergreen broadleaf 87379 CA 37.36 -122.13 112 2025-01-28 Yes Yes Yes 36 (12)
blue oak Semi-evergreen broadleaf 53668 CA 37.36 -122.13 112 2025-01-30 Yes Yes Yes 36 (12)
Table 4: Anomalous observations of open flowers or cones. ID = individual plant identification number. No. Prior Obs. (Yrs) lists the number of 2009-2024 observations (with the associated number of years) that were used to determine whether a 2025 observation was anomalous or not.
Species Functional type ID State Lat Lon Elev (m) Date Early Earliest Outlier No. Prior Obs. (Yrs)
star magnolia Deciduous broadleaf 79974 CA 38.38 -122.51 109 2025-02-06 Yes No No 27 (9)
brittlebush Drought deciduous broadleaf 246477 AZ 32.37 -110.97 800 2025-02-15 Yes No No 67 (10)
California live oak Evergreen broadleaf 270774 CA 37.93 -122.74 75 2025-01-12 Yes Yes Yes 141 (13)
California live oak Evergreen broadleaf 87339 CA 37.36 -122.13 97 2025-01-21 Yes No No 107 (13)
coyotebrush Evergreen broadleaf 18492 CA 37.98 -122.13 63 2025-01-06 Yes Yes Yes 334 (14)
creosote bush Evergreen broadleaf 102258 AZ 32.24 -110.91 755 2025-01-10 Yes Yes Yes 368 (16)
creosote bush Evergreen broadleaf 50751 AZ 32.25 -110.91 746 2025-01-12 Yes No Yes 368 (16)
creosote bush Evergreen broadleaf 199258 AZ 32.34 -110.98 764 2025-01-14 Yes No Yes 369 (16)
jojoba Evergreen broadleaf 199269 AZ 32.34 -110.98 764 2025-01-14 Yes Yes Yes 86 (13)
olive Evergreen broadleaf 347073 CA 37.57 -122.03 12 2025-01-16 Yes Yes Yes 20 (8)
Douglas-fir Evergreen conifer 28798 CA 37.93 -122.74 74 2025-01-18 Yes No No 24 (11)

Figure 1: Map of early phenological observations. Green leaves denote early observations of initial vegetative growth and/or leaves or needles, and purple flowers denote early observations of flowers or cones and/or open flowers or cones. Circles delineate the areas containing plants observed in prior years that were used for comparison. Blue shading indicates areas that were cooler than normal as of 2025-03-06 (>40 deg F below 30-year normals for accumulated growing degree days with 32 deg F base); orange shading indicates areas that were warmer than normal as of 2025-03-06 (>40 deg F above 30-year normals). Clicking on an icon will display the species name and individual plant ID.

Figure 2: Initial vegetative growth. Distributions of first-of-year observations in 2009-2024 that were used to assess whether a 2025 observation (red vertical line) was unusually early.
Figure 3: Leaves or needles. Distributions of first-of-year observations in 2009-2024 that were used to assess whether a 2025 observation (red vertical line) was unusually early.
Figure 4: Flowers or cones. Distributions of first-of-year observations in 2009-2024 that were used to assess whether a 2025 observation (red vertical line) was unusually early.
Figure 5: Open flowers or cones. Distributions of first-of-year observations in 2009-2024 that were used to assess whether a 2025 observation (red vertical line) was unusually early.